Battery pack and vehicle

ABSTRACT

The present disclosure provides a battery pack and a vehicle. The battery pack comprises a battery module, a box assembly and a first adhesive member. The battery module comprises first batteries arranged sequentially in a horizontal direction. The first battery comprises an electrode assembly and a case, and the electrode assembly is received in the case. The electrode assembly comprises a first electrode plate, a second electrode plate and a separator. The box assembly has a connection portion, and the connection portion is positioned at a side of the battery module in the vertical direction. An outer surface of the case comprises a first surface, and the first surface is connected with the connection portion via the first adhesive member. An area A of the first surface and an elastic modulus B of the first adhesive member satisfy a relationship: 0.02 cm2/MPa≤A/B≤9 cm2/MPa.

CROSS-REFERENCE To RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/691,234, filed on Nov. 21, 2019, which claimspriority to Chinese Patent Application No. 201910375558.0, filed withthe State Intellectual Property Office of the People's Republic of Chinaon May 7, 2019, all of which are incorporated herein by reference intheir entirety.

TECHNICAL FIELD

The present disclosure relates to the field of battery, and particularlyrelates to a battery pack and a vehicle.

BACKGROUND

A secondary battery has the advantages of high energy density, longworking life, energy saving, environmental protection and the like, andhas been widely applied to various fields, such as new energy vehicle,energy storage power station and the like.

A battery pack generally comprises a box assembly and a battery moduleaccommodated in the box assembly; the battery module comprises batteriesarranged sequentially. In known technology, the battery module fixes thebatteries by providing an end plate and a side plate, the end plate isfixed to the box assembly via a bolt, and the batteries of the batterymodule are not directly connected with the box assembly, so the overallstiffness of the battery module is low. When the battery modulevibrates, the battery positioned at middle of the battery module cannotbe easily fixed completely due to insufficient clamping force, therebyresulting in safety risk.

SUMMARY

In view of the problem existing in the background, an object of thepresent disclosure is to provide a battery pack and a vehicle, which canensure dynamics performance of the battery and connecting strengthbetween the battery and the box assembly.

In order to achieve the above object, the present disclosure provides abattery pack and a vehicle.

The battery pack comprises a battery module, a box assembly and a firstadhesive member. The box assembly has an accommodating cavity, thebattery module is positioned in the accommodating cavity of the boxassembly. The battery module comprises first batteries arrangedsequentially in a horizontal direction. The first battery comprises anelectrode assembly and a case, and the electrode assembly is received inthe case. The electrode assembly comprises a first electrode plate, asecond electrode plate and a separator provided between the firstelectrode plate and the second electrode plate. The electrode assemblyis a winding structure and in a flat shape, and the electrode assemblycomprises two flat surfaces, the two flat surfaces face each other in avertical direction; or, the electrode assembly is a stacking structure,the first electrode plate, the separator and the second electrode plateare stacked in the vertical direction. The box assembly has a connectionportion, and the connection portion is positioned at a side of thebattery module in the vertical direction. An outer surface of the casecomprises a first surface, and the first surface is connected with theconnection portion via the first adhesive member. An area A of the firstsurface and an elastic modulus B of the first adhesive member satisfy arelationship: 0.02 cm²/MPa≤A/B≤9 cm²/MPa.

The area A of the first surface and the elastic modulus B of the firstadhesive member satisfy a relationship: 0.06 cm²/MPa≤A/B≤4 cm²/MPa.

The area A of the first surface is 50 cm²-600 cm², the elastic modulus Bof the first adhesive member is 150 MPa-800 MPa.

The elastic modulus B of the first adhesive member and a thickness C ofthe first adhesive member satisfy a relationship: 2 MPa·cm≤B·C≤500MPa·cm.

The thickness C of the first adhesive member is 0.05 cm-0.5 cm.

The first adhesive member is an adhesive, and the adhesive is one ormore selected from a group consisting of epoxy resin, polyurethane andacrylic resin.

A dimension of the battery module in the horizontal direction is largerthan a dimension of the battery module in the vertical direction.

A contacting area between the first adhesive member and the firstsurface is defined as S1, a total area of the outer surface of the caseis defined as S2, a value of S1/S2 is larger than 6%.

The case further comprises a second surface and two third surfaces, thefirst surface and the second surface face each other in the verticaldirection, and the two third surfaces face each other in the horizontaldirection. Both of the area of the first surface and an area of thesecond surface are larger than an area of the third surface.

The battery module further comprises second batteries arrangedsequentially in the horizontal direction, the second battery and thefirst battery are stacked in the vertical direction, and the secondbattery is positioned at a side of the first battery close to the secondsurface. The battery pack further comprises a second adhesive member,and the second adhesive member connects the second surface and thesecond battery.

The case comprises an insulation layer and a base, the insulation layeris positioned at an outer side of the base and contacted with the firstadhesive member.

The box assembly comprises an upper box cover and a lower box body, theupper box cover and the lower box body are connected. The connectionportion is a bottom wall of the lower box body, the first adhesivemember is provided to the bottom wall of the lower box body, and thefirst surface is connected with the bottom wall of the lower box bodyvia the first adhesive member; or, the connection portion is a top wallof the upper box cover, the first adhesive member is provided to the topwall of the upper box cover, and the first surface is connected with thetop wall of the upper box cover via the first adhesive member.

The box assembly comprises an upper box cover, a lower box body and afixing plate, the upper box cover and the lower box body are connected,the connection portion is the fixing plate. The fixing plate ispositioned at an upper side of the battery module in the verticaldirection and connected with the upper box cover, the first adhesivemember is provided on the fixing plate, and the first surface isconnected with the fixing plate via the first adhesive member; or, thefixing plate is positioned at a lower side of the battery module in thevertical direction and connected with the lower box body, the firstadhesive member is provided on the fixing plate, and the first surfaceis connected with the fixing plate via the first adhesive member.

The vehicle comprises a vehicle body and the battery pack, the batterypack is positioned to the vehicle body. In some embodiments, the batterypack is horizontally provided to a bottom of the vehicle body.

The present disclosure has the following beneficial effects: in thepresent disclosure, the first batteries are fixed to the box assemblyvia the first adhesive member, thereby increasing the connectingstrength between the battery module and the box assembly, achieving thefixation of the first batteries, and reducing the safety risk when thebattery pack vibrates. In the present disclosure, the area A of thefirst surface and the elastic modulus B of the first adhesive member arecomprehensively considered, when “0.02 cm²/MPa≤A/B≤9 cm²/MPa” issatisfied, it can ensure the dynamics performance of the first batteryand the connecting strength between the first battery and the boxassembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a battery pack according to the presentdisclosure.

FIG. 2 is a schematic view of an embodiment of a first battery of thebattery pack according to the present disclosure.

FIG. 3 is a cross sectional view of an electrode assembly of FIG. 2.

FIG. 4 is a schematic view of another embodiment of the first battery ofthe battery pack according to the present disclosure.

FIG. 5 is a schematic view of the battery pack according to the presentdisclosure before the first battery expands.

FIG. 6 is a schematic view of the battery pack according to the presentdisclosure after the first battery expands.

FIG. 7 is an enlarged view of a part of FIG. 6 within a dotted-lineframe

FIG. 8 is a schematic view of a case of FIG. 6.

FIG. 9 is a schematic view of a battery in a test of shear strength.

REFERENCE NUMERALS IN FIGURES ARE REPRESENTED AS FOLLOWS

-   1 battery module    -   11 first battery        -   111 electrode assembly            -   111 a first electrode plate            -   111 b second electrode plate            -   111 c separator            -   111 d flat surface            -   111 e narrow surface        -   112 case            -   112 a first surface            -   112 b second surface            -   112 c third surface            -   112 d fourth surface        -   113 cap assembly            -   113 a cap plate            -   113 b electrode terminal    -   12 second battery-   2 box assembly    -   21 upper box cover    -   22 lower box body    -   23 fixing plate-   3 first adhesive member-   4 second adhesive member-   5 third adhesive member-   6 jig-   7 detector-   8 metal plate-   X length direction-   Y width direction-   Z vertical direction

DETAILED DESCRIPTION

To make the object, technical solutions and advantages of the presentdisclosure more apparent, hereinafter the present disclosure will befurther described in detail in combination with the accompanying figuresand the embodiments. It should be understood that the specificembodiments described herein are merely used to explain the presentdisclosure but are not intended to limit the present disclosure.

In the description of the present disclosure, unless otherwisespecifically defined and limited, the terms “first”, “second”, “third”,and “fourth” are only used for illustrative purposes and are not to beconstrued as expressing or implying a relative importance. The term“plurality” is two or more. Unless otherwise defined or described, theterm “connect” should be broadly interpreted, for example, the term“connect” can be “fixedly connect”, “detachably connect”, “integrallyconnect”, “electrically connect” or “signal connect”. The term “connect”also can be “directly connect” or “indirectly connect via a medium”. Forthe persons skilled in the art, the specific meanings of theabovementioned terms in the present disclosure can be understoodaccording to the specific situation.

In the description of the present disclosure, it should be understoodthat spatially relative terms, such as “above”, “below” and the like,are described based on orientations illustrated in the figures, but arenot intended to limit the embodiments of the present disclosure.Hereinafter the present disclosure will be further described in detailin combination with the exemplary embodiments and the figures.

In the description of the present disclosure, in the figures, thedirections indicated by arrows X are length directions, the directionsindicated by arrows Y are width directions, and the directions indicatedby arrows Z are vertical directions. A horizontal direction is adirection parallel to a horizontal plane, and the horizontal directionis either a length direction X or a width direction Y. In addition, thehorizontal direction not only includes a direction absolutely parallelto the horizontal plane, but also a direction substantially parallel tothe horizontal plane conventionally cognized in engineering. Thevertical direction is a direction perpendicular to the horizontal plane,the vertical direction not only includes a direction absolutelyperpendicular to the horizontal plane, but also a directionsubstantially perpendicular to the horizontal plane conventionallycognized in engineering. Furthermore, spatially relative terms, such as“above”, “below”, “top”, “bottom” and the like, described in the presentdisclosure, are understood relative to the vertical direction Z.

The present disclosure provides a vehicle, the vehicle comprises avehicle body and a battery pack, the battery pack is provided to thevehicle body. The vehicle is a new energy vehicle, for example, thevehicle may be a pure electric vehicle, hybrid power vehicle or extendedrange vehicle. The vehicle body is provided with a drive motor, thedrive motor is electrically connected with the battery pack, the batterypack supplies electric energy, and the drive motor is connected with awheel on the vehicle body via a transmission mechanism, thereby drivingthe vehicle. Preferably, the battery pack may be horizontally providedto a bottom of the vehicle body.

FIG. 1 is an exploded view of a battery pack according to the presentdisclosure. The battery pack comprises a battery module 1, a boxassembly 2 and a first adhesive member 3.

The box assembly 2 comprises an upper box cover 21 and a lower box body22. In FIG. 1, the upper box cover 21 and the lower box body 22 areseparated. The upper box cover 21 and the lower box body 22 areconnected together in sealing, and an accommodating cavity is formedbetween the upper box cover 21 and the lower box body 22. The upper boxcover 21 and the lower box body 22 may be made of aluminum, aluminumalloy or other metal.

The battery module 1 is accommodated in the accommodating cavity of thebox assembly 2. The battery module 1 may be provided as one or pluralityin number. When the battery module 1 is provided as plurality in number,the plurality of the battery modules 1 may be arranged in the lengthdirection X or arranged in the width direction Y. The battery module 1comprises first batteries 11 arranged sequentially in the horizontaldirection. The first batteries 11 are secondary batteries which cancharge and discharge repeatedly. The first batteries 11 may beelectrically connected via busbars.

The battery module 1 further comprises two end plates not shown in thefigures and a strap not shown in the figures. The two end plates arerespectively provided at two ends of the first batteries 11 in thehorizontal direction, the strap encircles the first batteries 11 and thetwo end plates. The end plate may be made of metal material, such asaluminum, aluminum alloy or the like, or made from insulation material.

Referring to FIG. 2, the first battery 11 comprises an electrodeassembly 111, a case 112 and a cap assembly 113. The electrode assembly111 is received in the case 112, and the electrode assembly 111comprises a first electrode plate 111 a,a second electrode plate 111 band a separator 111 c provided between the first electrode plate 111 aand the second electrode plate 111 b.

The case 112 may be made of metal material or composite material. Forexample, in an embodiment, the case 112 is integrally made of metalmaterial, such as aluminum, aluminum alloy, nickel-plated steel or thelike. Alternatively, in another embodiment, the case 112 may comprises abase and an insulation layer, the base is made of metal material, suchas aluminum, aluminum alloy, nickel-plated steel or the like, theinsulation layer is provided to an outer surface of the base by coating,bonding or the like; at this time, the base made of metal material canensure the strength of the case 112, and the insulation layer canpromote the insulating performance of the case 112.

The case 112 may have a hexahedron shape or other shape. The case 112has an opening, and the electrode assembly 111 can be placed into thecase 112 via the opening. In an embodiment, the opening is positioned atan end of the case 112 in the width direction Y.

The cap assembly 113 comprises a cap plate 113 a and an electrodeterminal 113 b, the electrode terminal 113 b is provided to the capplate 113 a. The cap plate 113 a may be made of metal material, such asaluminum, aluminum alloy or the like, a dimension of the cap plate 113 ais matched with a dimension of the opening of the case 112. The capplate 113 a is connected to the case 112 by welding and covers theopening of the case 112, thereby sealing the electrode assembly 111 inthe case 112.

The electrode terminal 113 b is fixed with the cap plate 113 a bywelding, riveting or the like. The electrode terminal 113 b is providedas two in number and the two electrode terminals 113 b are respectivelyelectrically connected with the first electrode plate 111 a and thesecond electrode plate 111 b.

In the electrode assembly 111, one of the first electrode plate 111 aand the second electrode plate 111 b is a positive electrode plate, theother one of the first electrode plate 111 a and the second electrodeplate 111 b is a negative electrode plate, and the separator 111 c is aninsulator provided between the positive electrode plate and the negativeelectrode plate. For example, the first electrode plate 111 a is thepositive electrode plate, the first electrode plate 111 a comprises afirst current collector and a first active material layer coated on asurface of the first current collector; the first current collector maybe an aluminum foil, the first active material layer comprises ternarymaterial, lithium manganese oxide or lithium iron phosphate. The secondelectrode plate 111 b is the negative electrode plate, and the secondelectrode plate 111 b comprises a second current collector and a secondactive material layer coated on a surface of the second currentcollector; the second current collector may be copper foil, the secondactive material layer comprises graphite or silicon.

As shown in FIG. 3, in an embodiment, the electrode assembly 111 is awinding structure. Specifically, the first electrode plate 111 a, thesecond electrode plate 111 b and the separator 111 c are belt-shapedstructures. The first electrode plate 111 a,the separator 111 c and thesecond electrode plate 111 b are stacked sequentially and wound to twoor more turns to form the electrode assembly 111, and the electrodeassembly 111 is in a flat shape. When preparing the electrode assembly111, the electrode assembly 111 is wound to a hollow cylindricalstructure, and then the electrode assembly 111 is pressed to a flatshape after winding. FIG. 3 is a schematic view showing a profile of theelectrode assembly 111. The outer surface of the electrode assembly 111comprises two flat surfaces 111 d and two narrow surfaces 111 e, the twoflat surfaces 111 d face each other in the vertical direction Z, the twonarrow surfaces 111 e face each other in the length direction X. Theflat surface 111 d is substantially parallel to a winding axis of theelectrode assembly 111. The flat surface 111 d is a relatively flatsurface and not required to be an absolute plane. At least a part of thenarrow surface 111 e is in the shape of arc. The flat surface 111 d isflat relative to the narrow surface 111 e, and an area of the flatsurface 111 d is larger than an area of the narrow surface 111 e.

As shown in FIG. 4, in another embodiment, the electrode assembly 111 isa stacking structure. Specifically, the electrode assembly 111 comprisesfirst electrode plates 111 a and second electrode plates 111 b; theseparator 111 c is provided between the first electrode plate 111 a andthe second electrode plate 111 b. The first electrode plates 111 a andthe second electrode plates 111 b are stacked in the vertical directionZ. In the stacking structure, the first electrode plate 111 a and thesecond electrode plate 111 b are in the shape of plate and substantiallyperpendicular to the vertical direction Z.

In the charge process or discharge process of the electrode assembly111, the electrode plate will expand along its thickness direction. Inthe electrode assembly 111 having winding structure, an expanding forcealong a direction perpendicular to the flat surface 111 is largest; inthe electrode assembly 111 having stacking structure, an expanding forcealong a stacking direction of the first electrode plates 111 a and thesecond electrode plates 111 b is largest. This shows that whether theelectrode assembly 111 is a winding structure or a stacking structure,the largest expanding force applied to the case 112 by the electrodeassembly 111 is along a direction substantially parallel to the verticaldirection Z. In other words, in the horizontal direction, the electrodeassembly 11 applies a smaller expanding force to the case 112. In thepresent disclosure, the first batteries 11 are arranged in the lengthdirection X, so even though the expanding forces of all the electrodeassemblies 111 in the length direction X are accumulated to form acomposite force, and the composite force will not be excessive, therebyreducing a risk that the first batteries 11 is crushed.

The box assembly 2 has a connection portion, and the connection portionis positioned at a side of the battery module 1 in the verticaldirection Z. An outer surface of the case 112 comprises a first surface112 a, and the first surface 112 a is connected with the connectionportion via the first adhesive member 3. The first surface 112 a ispositioned at an end of the case 112 close to the connection portion,and the first adhesive member 3 may be provided between the firstsurface 112 a and the connection portion and connected with the firstsurface 112 a and the connection portion. The first batteries 11 and thebox assembly 2 are connected via the first adhesive member 3.

In an embodiment, a bottom wall of the lower box body 22 may act as theconnection portion, the first adhesive member 3 is provided to thebottom wall of the lower box body 22; at this time, the first batteries11 can be provided close to the bottom wall of the lower box body 22,the first surface 112 a is connected with the bottom wall of the lowerbox body 22 via the first adhesive member 3.

In another embodiment, a top wall of the upper box cover 21 also can actas the connection portion, the first adhesive member 3 is provided tothe top wall of the upper box cover 21; at this time, the firstbatteries 11 can be provided close to the top wall of the upper boxcover 21, and the first surface 112 a is connected with the top wall ofthe upper box cover 21 via the first adhesive member 3.

In still another embodiment, the box assembly 2 further comprises afixing plate 23, and the fixing plate 23 also can act as the connectionportion. The fixing plate 23 is accommodated in the accommodating cavityand positioned at an upper side of the battery module 1 in the verticaldirection Z, and the fixing plate 23 is fixed with the upper box cover21 via a fastener. The first adhesive member 3 is provided on the fixingplate 23, and the first surface 112 a is connected with the fixing plate23 via the first adhesive member 3. A gap is kept between the fixingplate 23 and the top wall of the upper box cover 21, and the gap canavoid deformation of the upper box cover 21 due to expansion of thefirst batteries 11 in the vertical direction Z.

In further another embodiment, referring to FIG. 1, the fixing plate 23is accommodated in the accommodating cavity and positioned at a lowerside of the battery module 1 in the vertical direction Z, and the fixingplate 23 can be fixed with the lower box body 22 via a fastener. Thefirst adhesive member 3 is provided on the fixing plate 23, and thefirst surface 112 a is connected with the fixing plate 23 via the firstadhesive member 3. A gap is kept between the fixing plate 23 and thebottom wall of the lower box body 22, and the gap can avoid deformationof the lower box body 22 due to expansion of the first batteries 11 inthe vertical direction Z.

The first adhesive member 3 is a solid adhesive, the adhesive is liquidor paste before solidification, the adhesive is coated between theconnection portion and the first surface 112 a of the first battery 11and solidifies, thereby firmly connecting the first battery 11 and thebox assembly 2. The adhesive is one or more selected from a groupconsisting of epoxy resin, polyurethane and acrylic resin.

In the present disclosure, the first batteries 11 are fixed to the boxassembly 2 via the first adhesive member 3, thereby increasing theconnecting strength between the battery module 1 and the box assembly 2,achieving the fixation of the first batteries 11, and reducing thesafety risk when the battery pack vibrates.

In the charge process or discharge process of the electrode assembly111, the electrode assembly 111 applies an expanding force to acircumferential wall of the case 112, and a first side wall of the case112 corresponding to the first surface 112 a is subjected to a largestexpanding force and deforms most easily. Edge region of the first sidewall corresponding to the first surface 112 a is bound by other sidewalls, and an central region of the first side wall is subjected to asmaller bound force, so when the first side wall is subjected to theexpanding force, the central region of the first side wall will bulge.Correspondingly, referring to FIG. 8, a height difference h will existbetween the central region of the first surface 112 a and the edgeregion of the first surface 112 a.

An area of the first surface 112 a is defined as A. The larger the valueof A is, the smaller the bound force applied to the central region ofthe first side wall is, and the more the deformation of the centralregion of the first side wall is, that is, the larger the value of h is.The smaller the value of A is, the larger the bound force applied to thecentral region of the first side wall is, and the less the deformationof the central region of the first side wall is, that is, the smallerthe value of h is.

When the electrode assembly 111 expands, the first side wall applies areaction force to the electrode assembly 111. The larger the value of Ais, the more the deformation of the first side wall is; the first sidewall can release the expanding force by deformation, correspondingly,the reaction force applied to the electrode assembly 111 by the firstside wall can be decreased. The smaller the value of A is, the less thedeformation of the first side wall is, and the lower the capability ofthe first side wall to release the expanding force is; correspondingly,the first side wall will apply a larger reaction force to the electrodeassembly 111. When the reaction force applied to the electrode assembly111 is excessively large, an electrolyte between the first electrodeplate 111 a and the second electrode plate 111 b is easily extruded out,which leads to the infiltration capability of partial region beingreduced, the lithium-ion being unable to pass through the separator 111c and causes the lithium precipitation.

An elastic modulus of the first adhesive member 3 is defined as B. Thelarger the value of B is, the higher the stiffness of the first adhesivemember 3 is, and the less easily the first adhesive member 3 deformswhen it is subjected to force. The smaller the value of B is, the lowerthe stiffness of the first adhesive member 3 is, and the more easily thefirst adhesive member 3 deforms when it is subjected to force. Inaddition, to a certain extent, the value of B is directly proportionalto the bonding strength of the first adhesive member 3.

When the electrode assembly 111 expands, the first side wall will deformunder the influence of the expanding force. At the same time, referringto FIG. 6 and FIG. 7, the first surface 112 a will also press the firstadhesive member 3.

The larger the value of B is, the less easily the first adhesive member3 deforms; the first adhesive member 3 is bonded with the first surface112 a, so the first adhesive member 3 will limit the deformation of thefirst surface 112 a too. In other words, the larger the value of B is,the smaller the deformation of the first side wall is, the greater thereaction force applied to the electrode assembly 111 by the first sidewall is, the more easily the electrolyte in the electrode assembly 111is extruded out, and the higher a risk of lithium precipitation is.

The smaller the value of B is, the more easily the first adhesive member3 deforms; in other words, the smaller the value of B is, the more thedeformation of the first side wall is, the less the reaction forceapplied to the electrode assembly 111 by the first side wall is, and thelower a risk that the electrolyte is extruded out is. However, theeasier the first surface 112 a deforms, the larger the height differenceh between the central region and the edge region is; referring to FIG. 7and FIG. 8, although a part of the first adhesive member 3 contactingthe central region of the first surface 112 a is pressed, a part of thefirst adhesive member 3 contacting the edge region of the first surface112 a is stretched easily. The smaller the value of B is, the lower thebonding strength of the first adhesive member 3 is; when the firstadhesive member 3 is stretched, the first adhesive member 3 is easilyseparated from the first surface 112 a or the connection portion, whichleads to the connecting strength between the first battery 11 and theconnection portion being lower, and results in a risk that the firstbattery 11 is detached from the box assembly 2.

In conclusion, the area A of the first surface 112 a and the elasticmodulus B of the first adhesive member 3 have an significant influenceon the dynamics performance of the first battery 11 and the connectingstrength between the first battery 11 and the box assembly 2. In thepresent disclosure, the area A of the first surface 112 a and theelastic modulus B of the first adhesive member 3 are comprehensivelyconsidered, when “0.02 cm²/MPa≤A/B≤9 cm²/MPa” is satisfied, it canensure the dynamics performance of the first battery 11 and theconnecting strength between the first battery 11 and the box assembly 2.

Specifically, if “A/B≤0.02 cm²/MPa”, the value of A is smaller and thevalue of B is larger. When the electrode assembly 111 of the firstbattery 11 expands, because the value of A is smaller, the deformationcapability of the first side wall is limited; and because the value of Bis larger, the first adhesive member 3 will further limit thedeformation of the first side wall. At this time, the deformation of thefirst side wall is limited, so the first side wall will apply a largerreaction force to the electrode assembly 111, the electrolyte in theelectrode assembly 111 will be extruded out, which leads to theinfiltration capability of partial region being reduced, the lithium-ionbeing unable to pass through the separator 111 c and causes the lithiumprecipitation.

If “A/B>9 cm²/MPa”, the value of A is larger and the value of B issmaller. When the electrode assembly 111 of the first battery 11expands, because the value of A is larger, the deformation of the firstside wall is also more; correspondingly, the first surface 112 a iseasier to deform, and the height difference h between the central regionof the first surface 112 a and the edge region of first surface 112 a isalso larger. Because the value of B is smaller, the first adhesivemember 3 cannot effectively limit the deformation of the first surface112 a, which leads to the height difference h between the central regionof the first surface 112 a and the edge region of first surface 112 abeing excessive large, and a part of the first adhesive member 3contacting the edge region of the first surface 112 a being stretchedmore easily. When the first adhesive member 3 is stretched, the firstadhesive member 3 is more easily separated from the first surface 112 aor the connection portion, which leads to the connecting strengthbetween the first battery 11 and the connection portion being lower, andresults in a risk that the first battery 11 is detached from the boxassembly 2.

Preferably, the area A of the first surface 112 a and the elasticmodulus B of the first adhesive member 3 satisfy a relationship: 0.06cm²/MPa≤A/B≤4 cm²/MPa.

The area A of the first surface 112 a is 20 cm²-900 cm², preferably 50cm²-600 cm². The elastic modulus B of the first adhesive member 3 is 100Mpa-1000 Mpa, preferably 150 MPa-800 MPa.

A thickness of the first adhesive member 3 is defined as C. When theelectrode assembly 111 of the first battery 11 expands, the part of thefirst adhesive member 3 contacting the edge region of the first surface112 a is stretched easily. The larger the value of C is, the greater alength of the first adhesive member 3 capable of being stretched beforethe first adhesive member 3 is separated from the first surface 111 a orthe connection portion is; otherwise, the smaller the value of C is, andthe less the length of the first adhesive member 3 capable of beingstretched is. In addition, the smaller the value of B is, the moreeasily the first adhesive member 3 is stretched.

When the electrode assembly 111 of the first battery 11 expands, if thevalue of B is smaller and the value of A is larger, the first surface112 a is easier to deform, the height difference h between the centralregion of the first surface 112 a and the edge region of the firstsurface 112 a is larger. At this time, the part of the first adhesivemember 3 contacting the edge region of the first surface 112 a needs tobe stretched to a larger length, to avoid the first adhesive member 3being separated from the first surface 112 or the connection portion.Therefore, the thickness C of the first adhesive member 3 needs to havea larger value.

When the electrode assembly 111 of the first battery 11 expands, if thevalue of B is larger and the value of A is smaller, the first surface112 a is less easy to deform, the height difference h between thecentral region of the first surface 112 a and the edge region of thefirst surface 112 a is smaller. At this time, the part of the firstadhesive member 3 contacting the edge region of the first surface 112 awill be stretched to a smaller length. Therefore, the thickness C of thefirst adhesive member 3 can has a smaller value, to decease the usageamount of the adhesive, reduce cost and improve energy density.

In conclusion, the elastic modulus B of the first adhesive member 3 andthe thickness C of the first adhesive member 3 have an significantinfluence on the connecting strength between the first battery 11 andthe box assembly 2. In the present disclosure, the elastic modulus B ofthe first adhesive member 3 and the thickness C of the first adhesivemember 3 are comprehensively considered, when a relationship, 2MPa·cm≤B·C≤500 MPa·cm, is satisfied, it can ensure the connectingstrength between the first battery 11 and the box assembly 2.

If “B·C<2 MPa·cm”, both the value of B and the value of C are smaller,the first adhesive member 3 is easily separated from the first surface112 or the connection portion. If “B·C>500 MPa·cm”, the value of C islarger, which results in waste of the adhesive, more inner space of thebox assembly 2 being occupied.

The thickness C of the first adhesive member 3 is 0.02 cm-1 cm,preferably 0.05 cm-0.5 cm.

A roughness of the first surface 112 a is 0.01 μm-2 μm. If the roughnessof the first surface 112 a is smaller than 0.01 μm, the first surface112 a is excessively smooth, which is not beneficial for bonding thefirst surface 112 a and the first adhesive member 3, and reduces theconnecting strength between the first surface 112 a and the connectionportion.

The case 112 is substantially in a shape of hexahedron. Specifically,referring to FIG. 2 and FIG. 5, the case 112 further comprises a secondsurface 112 b, two third surfaces 112 c and a fourth surface 112 d. Thesecond surface 112 b is positioned at an end of the case 112 away fromthe connection portion in the vertical direction Z, the second surface112 b and the first surface 112 a face each other in the verticaldirection Z. The two third surfaces 112 c are respectively positioned attwo ends of the case 112 in the length direction X and face each otherin the length direction X. The fourth surface 112 d is positioned at andend of the case 112 in the width direction Y.

Before the electrode assembly 111 expands, the first surface 112 a andthe second surface 112 b are substantially planar surfaces perpendicularto the vertical direction Z, the two third surfaces 112 c aresubstantially planar surfaces perpendicular to the length direction X,the fourth surface 112 d is substantially planar surface perpendicularto the width direction Y. The first surface 112 a, the third surface 112c and the fourth surface 112 d are connected with each other viatransition surfaces in the shape of arc. The second surface 112 b, thethird surface 112 c and the fourth surface 112 d are connected with eachother via transition surfaces in the shape of arc.

Both of the area of the first surface 112 a and an area of the secondsurface 112 b are larger than an area of the third surface 112 c. Theelectrode assembly 111 generates gas in the charge process or dischargeprocess, and the gas will apply a force to the case 112, therebyintensifying outward expansion of the case 112. In an embodiment, bothof the area of the first surface 112 a and the area of the secondsurface 112 b are larger than the area of the third surface 112 c, andthe first surface 112 a and the second surface 112 b face each other inthe vertical direction Z, so a direction of a largest force applied tothe case 112 by the gas is along the vertical direction Z. Compared toknown technology, it can further decrease the largest expanding force ofthe battery module 1.

A contacting area between the first adhesive member 3 and the firstsurface 112 a is defined as S1, a total area of the outer surface of thecase 112 is defined as S2, a value of S1/S2 is larger than 6%. The totalarea of the outer surface of the case 112 is a sum of the area of thefirst surface 111 a, the area of the second surface 111 b, the areas ofthe two third surfaces 111 c, an area of the fourth surface 111 d andareas of the transition surfaces in the shape of arc.

The larger a value of S1 is, the greater a bonding force between thefirst adhesive member 3 and the first battery 11 is; otherwise, thesmaller the value of S1 is, the less the bonding force between the firstadhesive member 3 and the first battery 11 is. The larger a value of S2is, the larger a volume of the first battery 11 is, the larger a weightof the first battery 11 is, and the greater the bonding force the firstbattery 11 needs to have is; otherwise, the smaller the value of S2 is,the less the bonding force the first battery 11 needs to have is. In thepresent disclosure, the value of S1 and the value of S2 arecomprehensively considered, when the value of S1/S2 is larger than 6%,it can ensure the connecting strength between the first adhesive member3 and the first battery 11.

The battery module 1 further comprises second batteries 12 arrangedsequentially in the horizontal direction, the second battery 12 and thefirst battery 11 are stacked in the vertical direction Z, and the secondbattery 12 is positioned at a side of the first battery 11 close to thesecond surface 112 b. The second battery 12 and the first battery 11 arethe same battery.

A dimension of the battery module 1 in the horizontal direction islarger than a dimension of the battery module 1 in the verticaldirection Z. In the present disclosure, it can reduce a number of layersof the batteries stacked in the vertical direction Z, so as to decreasethe largest expanding force of the battery module 1, and avoid thebatteries being crushed. In addition, a height dimension of a chassis ofthe vehicle body is limited, so the battery module 1 preferably has asmaller dimension in the vertical direction Z.

Referring to FIG. 1, the battery pack further comprises a secondadhesive member 4, and the second adhesive member 4 connects the secondsurface 112 b and the second battery 12. The second adhesive member 4 isprovided between the second surface 112 b and the second battery 12, andbonds the first battery 11 and the second battery 12 together. Thesecond adhesive member 4 is an adhesive.

An area of the second surface 112 b is defined as D, and an elasticmodulus of the second adhesive member 4 is defined as E. In the presentdisclosure, the area D of the second surface 112 b is substantially sameas the area A of the first surface 112 a. The second adhesive member 4and the first adhesive member 3 can use the same adhesive, the elasticmodulus E of the second adhesive member 4 is substantially same as theelastic modulus B of the first adhesive member 3. Preferably, 0.02cm²/MPa≤D/E≤9 cm²/MPa.

Referring to FIG. 1 and FIG. 5, the battery pack further comprises athird adhesive member 5, the third adhesive member 5 bonds the thirdsurfaces 112 c of two adjacent first batteries 11. A connecting areabetween the third adhesive member 5 and the third surface 112 c isdefined as S3, an area of the third surface 112 c is defined as S4, andthe value of S3/S4 is 0.25-0.8. If the value of S3/S4 is smaller than0.25, the connecting strength between the third adhesive member 5 andthe third surface 112 c will be poor; on the premise that the connectingstrength is satisfied, it can decrease the value of S3 and saveadhesive; therefore, the value of S3/S4 is preferably smaller than 0.8.

Hereinafter the present disclosure will be further described in detailin combination with the examples.

A battery pack of an example 1 could be prepared according to thefollowing steps:

(i) NCM523 (positive active material), acetylene black (conductiveagent) and PVDF (binder) according to a mass ratio of 96:2:2 wereuniformly mixed with NMP (solvent), which then became homogeneous understirring via a vacuum mixer, a positive slurry was obtained; then thepositive slurry was uniformly coated on an aluminum foil, drying wasthen performed under room temperature and continual drying was performedin an oven, which was then followed by cold pressing, slitting and platecutting, finally the positive electrode plate was obtained.

(ii) Graphite or a mixer of graphite and other active materials with acertain mass ratio (negative active material), acetylene black(conductive agent), CMC (thickening agent) and SBR (binder) according toa mass ratio of 96.4:1:1.2:1.4 were uniformly mixed with deionized water(solvent), which then became homogeneous under stirring via a vacuummixer, a negative slurry was obtained; then the negative slurry wasuniformly coated on a copper foil, drying was then performed under roomtemperature and continual drying was performed in an oven, which wasthen followed by cold pressing, slitting and plate cutting, finally thenegative electrode plate was obtained.

(iii) Ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethylcarbonate (DEC) according to a volume ratio of 1:1:1 were mixed togetherto obtain an organic solvent, then sufficiently dried LiPF₆ (lithiumsalt) was dissolved into the mixed organic solvent to obtain anelectrolyte, and a concentration of the electrolyte was 1 mol/L.

(iv) The separator was a polyethylene membrane.

(v) The first electrode plate 111 a, the separator 111 c and the secondelectrode plate 111 b were stacked sequentially and wound to turns,which then was pressed to a flat shape to form an electrode assembly111. The electrode assembly 111 had two flat surfaces 111 d.

(vi) The electrode assembly 111 and a cap assembly 113 were connected,then the electrode assembly 111 was placed into the case 112, and a capplate 113 a of the cap assembly 113 was welded with the case 112;finally, after electrolyte injection, standby, formation, shaping andthe like, a battery was obtained. An area A of a first surface 111 a ofthe case 112 parallel to a flat surface 111 d of the electrode assembly111 was 300 cm².

(vii) A layer of adhesive was coated on a metal plate 8, and then thefirst surface 111 a of the case 112 was bonded to the adhesive.

(viii) A first adhesive member 3 was formed after curing the adhesive,and an elastic modulus B of the first adhesive member 3 was 100 Mpa, athickness C of the first adhesive member 3 was 0.2 cm.

In addition, it could adjust the thickness C of the first adhesivemember 3 by changing the coated thickness of the adhesive in step (vii),and it could adjust the elastic modulus B of the first adhesive member 3by changing the component of the adhesive. After step (viii), it couldcut a part of the first adhesive member 3, and measure the elasticmodulus B of the first adhesive member 3 by using a DMA-Q800 detector. Athickness of the battery in a direction perpendicular to the firstsurface 111 a was 5 cm.

Battery packs of examples 2-35 and battery packs of comparative examples1-5 all could be prepared in accordance with the preparing method of thebattery pack of the example 1. The differences among the battery packsof the examples 1-35 and the battery packs of comparative examples 1-5were the area A of the first surface 111 a, the elastic modulus B of thefirst adhesive member 3 and the thickness C of the first adhesive member3. Specific parameters were shown in the table 1.

Hereinafter test processes of the battery packs prepared in the examples1-35 and the comparative examples 1-5 were described.

Test of Shear Strength.

At 25° C., the batteries prepared in the examples 1-35 and thecomparative examples 1-5 were charged at a constant current of 3 C anddischarged at a constant current of 1 C for 2000 cycles. After 2000cycles of charge and discharge, the metal plate 8 was fixed to a jig 6of a shear testing machine, and the battery was clamped by a detector 7;then the detector 7 moved the battery at a speed of 5 mm/min along adirection parallel to the first adhesive member 3, and the detector 7would automatically generate values of pull forces and record a value Fof pull force when the metal plate 8 was separated from the battery. Thevalue of F/A was a shear strength. When the value of F/A was larger than2 MPa, it could satisfy battery's requirement of shear strength. Theshear testing machine might be a microcomputer control electronicuniversal testing machine (type: MTS-CMT 6502 or MTS-CMT 4104-BZ).

Test of Dynamics Performance.

At 25° C., the batteries prepared in the examples 1-35 and thecomparative examples 1-5 were charged at a constant current of 3 C anddischarged at a constant current of 1 C for 2000 cycles. After 2000cycles of charge and discharge, the second electrode plate 111 b wasdisassembled from the battery, and the lithium precipitation of thesecond electrode plate was observed. A ratio of thelithium-precipitation area of the second electrode plate 111 b to thetotal area of the second electrode plate 111 b less than 5% wasconsidered to be slight lithium precipitation, a ratio of thelithium-precipitation area of the second electrode plate 111 b to thetotal area of the second electrode plate 111 b between 5%-40% wasconsidered to be moderate lithium precipitation, a ratio of thelithium-precipitation area of the second electrode plate 111 b to thetotal area of the second electrode plate 111 b more than 40% wasconsidered to be serious lithium precipitation.

In order to avoid the test of shear strength and the test of dynamicsperformance influencing each other, each example was provided as tensets; five sets of each example were used for testing the shearstrength, and the values of F/A obtained in the five sets were averaged;the other five sets of each example were used for testing dynamicsperformance, and the ratios obtained in the other five sets wereaveraged.

Referring to the examples 1-35 and the comparative examples 1-2, whenthe value of A/B was smaller than 0.02 cm²/MPa, the case 112 would applya larger reaction force to the electrode assembly 111, the electrolytein the electrode assembly 111 would be extruded out, which lead to theinfiltration capability of partial region being reduced, the lithium-ionbeing unable to pass through the separator 111 c and caused a largerlithium precipitation area of the second electrode plate 111 b. When thevalue of A/B was larger than or equal to 0.02 cm²/MPa, it couldeffectively decrease the reaction force applied to the electrodeassembly 111, and promote the infiltration capability of the electrodeassembly 111 and reduce the lithium precipitation area of the secondelectrode plate 111 b.

Referring to the examples 1-35 and the comparative examples 3-5, whenthe value of A/B was larger than 9 cm²/MPa, the shear strength betweenthe battery and the metal plate 8 was smaller than 2 MPa, which couldnot satisfy the battery's requirement of shear strength. In an actualbattery pack, if the shear strength between the battery and the boxassembly 2 was smaller than 2 MPa, when the battery pack vibrated, thebattery was easily separated from the box assembly 2. When the value ofA/B was smaller than or equal to 9 cm²/MPa, the shear strength betweenthe battery and the metal plate 8 was larger than 2 MPa, which satisfiedthe battery's requirement of shear strength.

According to the examples 1-35 and the comparative examples 1-5, when“0.02 cm²/MPa≤A/B≤9 cm²/MPa”, it could ensure the dynamics performanceof the battery and the connecting strength between the battery and thebox assembly 2 at the same time.

Referring to the examples 1-10, when the value of area A of the firstsurface 111 a and the value of thickness C of the first adhesive member3 were constant, by changing the elastic modulus B of the first adhesivemember 3, it could adjust the shear strength between the battery and themetal plate 8. According to the examples 1-10, when the value of area Aand the value of thickness C were constant, the value of B wassubstantially directly proportional to the shear strength (the value ofF/A).

Referring to the example 5 and the examples 11-19, when the value of theelastic modulus B of the first adhesive member 3 and the value of thethickness C of the first adhesive member 3 were constant, by changingthe area A of the first surface 111 a, it could adjust the shearstrength between the battery and the metal plate 8. According to example5 and examples 11-19, when the value of the elastic modulus B and thevalue of thickness C were constant, the value of A was substantiallyinversely proportional to the shear strength (the value of F/A).

Referring to the example 5 and the examples 26-30, when the value ofarea A of the first surface 111 a and the value of the elastic modulus Bof the first adhesive member 3 were constant, by changing the thicknessC of the first adhesive member 3, it could adjust the shear strengthbetween the battery and the metal plate 8. According to the example 5and the examples 26-30, when the value of the area A and the value ofthe elastic modulus B were constant, the value of C was substantiallydirectly proportional to the shear strength (the value of F/A).

Referring to the comparative examples 4-5, when the value of AB waslarger than 9 cm²/MPa, the shear strength between the battery and metalplate 8 was insufficient. However, according to the comparative examples4-5, by increasing the value of C, it might improve the shear strengthbetween the battery and the metal plate 8.

TABLE 1 Parameters and test results of examples 1-35 and comparativeexamples 1-5 A B C F A/B B · C F/A Dynamics (cm²) (Mpa) (cm) (KN)(cm²/MPa) (MPa · cm) (MPa) performance Example 1 300 100 0.2 226 3 207.5 Slight lithium precipitation Example 2 300 200 0.2 251 1.5 40 8.3Slight lithium precipitation Example 3 300 300 0.2 276 1 60 9.2 Slightlithium precipitation Example 4 300 400 0.2 316 0.75 80 10.5 Slightlithium precipitation Example 5 300 500 0.2 363 0.6 100 12.1 Slightlithium precipitation Example 6 300 600 0.2 415 0.5 120 13.8 Slightlithium precipitation Example 7 300 700 0.2 464 0.43 140 15.4 Slightlithium precipitation Example 8 300 800 0.2 490 0.38 160 16.3 Slightlithium precipitation Example 9 300 900 0.2 515 0.33 180 17.1 Slightlithium precipitation Example 10 300 1000 0.2 535 0.3 200 17.8 Slightlithium precipitation Example 11 50 500 0.2 168 0.1 100 33.6 Slightlithium precipitation Example 12 100 500 0.2 243 0.2 100 24.3 Slightlithium precipitation Example 13 200 500 0.2 312 0.4 100 15.6 Slightlithium precipitation Example 14 400 500 0.2 412 0.8 100 10.3 Slightlithium precipitation Example 15 500 500 0.2 445 1 100 8.9 Slightlithium precipitation Example 16 600 500 0.2 486 1.2 100 8.1 Slightlithium precipitation Example 17 700 500 0.2 525 1.4 100 7.5 Slightlithium precipitation Example 18 800 500 0.2 552 1.6 100 6.9 Slightlithium precipitation Example 19 900 500 0.2 594 1.8 100 6.6 Slightlithium precipitation Example 20 20 1000 0.2 90.4 0.02 200 45.2 Slightlithium precipitation Example 21 100 1000 0.2 314 0.1 200 31.4 Slightlithium precipitation Example 22 200 1000 0.2 442 0.2 200 22.1 Slightlithium precipitation Example 23 900 100 0.2 189 9 20 2.1 Slight lithiumprecipitation Example 24 900 200 0.2 333 4.5 40 3.7 Slight lithiumprecipitation Example 25 900 300 0.2 459 3 60 5.1 Slight lithiumprecipitation Example 26 300 500 0.02 246 0.6 10 8.2 Slight lithiumprecipitation Example 27 300 500 0.1 301 0.6 50 10.0 Slight lithiumprecipitation Example 28 300 500 0.3 441 0.6 150 14.7 Slight lithiumprecipitation Example 29 300 500 0.4 492 0.6 200 16.4 Slight lithiumprecipitation Example 30 300 500 0.5 525 0.6 300 17.5 Slight lithiumprecipitation Example 31 300 1000 0.5 582 0.3 500 19.4 Slight lithiumprecipitation Example 32 300 800 0.5 561 0.38 400 18.7 Slight lithiumprecipitation Example 33 300 100 0.02 183 3 2 6.1 Slight lithiumprecipitation Example 34 300 200 0.02 201 1.5 4 6.7 Slight lithiumprecipitation Example 35 300 300 0.02 225 1 6 7.5 Slight lithiumprecipitation Comparative 10 1000 0.2 62.9 0.01 200 62.9 Serious example1 lithium precipitation Comparative 10 800 0.2 54.6 0.013 160 54.6Moderate example 2 lithium precipitation Comparative 900 50 0.2 63 45 100.7 Slight lithium example 3 precipitation Comparative 500 50 0.2 70 1010 1.4 Slight lithium example 4 precipitation Comparative 500 50 1 80 1050 1.6 Slight lithium example 5 precipitation

Furthermore, the embodiments of the present disclosure further providean apparatus, which includes a battery pack according to any one of theembodiments as described above, wherein the battery pack is adapted toprovide power for the apparatus. The apparatus may be an electricvehicle, a hybrid vehicle, an electric scooter, an electric cart or anyother suitable devices which can include the battery pack as their ownpower source.

What is claimed is:
 1. A battery pack, comprising a battery module, abox assembly and a first adhesive member; the box assembly having anaccommodating cavity, the battery module being positioned in theaccommodating cavity of the box assembly; the battery module comprisingfirst batteries arranged sequentially in a horizontal direction; thefirst battery comprising an electrode assembly and a case, and theelectrode assembly being received in the case; the electrode assemblycomprising a first electrode plate, a second electrode plate and aseparator provided between the first electrode plate and the secondelectrode plate; the electrode assembly being a winding structure and ina flat shape, and the electrode assembly comprising two flat surfaces,the two flat surfaces facing each other in a vertical direction; or, theelectrode assembly being a stacking structure, the first electrodeplate, the separator and the second electrode plate being stacked in thevertical direction; the box assembly having a connection portion, andthe connection portion being positioned at a side of the battery modulein the vertical direction; an outer surface of the case comprising afirst surface, and the first surface being connected with the connectionportion via the first adhesive member; an area A of the first surfaceand an elastic modulus B of the first adhesive member satisfying arelationship:0.02 cm²/MPa≤A/B≤9 cm²/MPa.
 2. The battery pack according to claim 1,wherein the area A of the first surface and the elastic modulus B of thefirst adhesive member satisfy a relationship:0.06 cm²/MPa≤A/B≤4 cm²/MPa.
 3. The battery pack according to claim 1,wherein the area A of the first surface is 50 cm²-600 cm²; the elasticmodulus B of the first adhesive member is 150 MPa-800 MPa.
 4. Thebattery pack according to claim 2, wherein the area A of the firstsurface is 50 cm²-600 cm²; the elastic modulus B of the first adhesivemember is 150 MPa-800 MPa.
 5. The battery pack according to claim 1,wherein the elastic modulus B of the first adhesive member and athickness C of the first adhesive member satisfy a relationship:2 MPa·cm≤B·C≤500 MPa·cm.
 6. The battery pack according to claim 5,wherein the thickness C of the first adhesive member is 0.05 cm-0.5 cm.7. The battery pack according to claim 2, wherein the elastic modulus Bof the first adhesive member and a thickness C of the first adhesivemember satisfy a relationship:2 MPa·cm≤B·C≤500 MPa·cm.
 8. The battery pack according to claim 1,wherein the first adhesive member is an adhesive, and the adhesive isone or more selected from a group consisting of epoxy resin,polyurethane and acrylic resin.
 9. The battery pack according to claim2, wherein the first adhesive member is an adhesive, and the adhesive isone or more selected from a group consisting of epoxy resin,polyurethane and acrylic resin.
 10. The battery pack according to claim1, wherein a dimension of the battery module in the horizontal directionis larger than a dimension of the battery module in the verticaldirection.
 11. The battery pack according to claim 1, wherein acontacting area between the first adhesive member and the first surfaceis defined as S1, a total area of the outer surface of the case isdefined as S2, a value of S1/S2 is larger than 6%.
 12. The battery packaccording to claim 1, wherein the outer surface of the case furthercomprises a second surface and two third surfaces, the first surface andthe second surface face each other in the vertical direction, and thetwo third surfaces face each other in the horizontal direction; both ofthe area of the first surface and an area of the second surface arelarger than an area of the third surface.
 13. The battery pack accordingto claim 12, wherein the battery module further comprises secondbatteries arranged sequentially in the horizontal direction, the secondbattery and the first battery are stacked in the vertical direction, andthe second battery is positioned at a side of the first battery close tothe second surface; the battery pack further comprises a second adhesivemember, and the second adhesive member connects the second surface andthe second battery.
 14. The battery pack according to claim 1, whereinthe case comprises an insulation layer and a base, the insulation layeris positioned at an outer side of the base and contacted with the firstadhesive member.
 15. The battery pack according to claim 1, wherein thebox assembly comprises an upper box cover and a lower box body, theupper box cover and the lower box body are connected; the connectionportion is a bottom wall of the lower box body, the first adhesivemember is provided to the bottom wall of the lower box body, and thefirst surface is connected with the bottom wall of the lower box bodyvia the first adhesive member; or, the connection portion is a top wallof the upper box cover, the first adhesive member is provided to the topwall of the upper box cover, and the first surface is connected with thetop wall of the upper box cover via the first adhesive member.
 16. Thebattery pack according to claim 1, wherein the box assembly comprises anupper box cover, a lower box body and a fixing plate, the upper boxcover and the lower box body are connected, the connection portion isthe fixing plate; the fixing plate is positioned at an upper side of thebattery module in the vertical direction and connected with the upperbox cover, the first adhesive member is provided on the fixing plate,and the first surface is connected with the fixing plate via the firstadhesive member; or, the fixing plate is positioned at a lower side ofthe battery module in the vertical direction and connected with thelower box body, the first adhesive member is provided on the fixingplate, and the first surface is connected with the fixing plate via thefirst adhesive member.
 17. A vehicle, comprising a vehicle body and abattery pack, the battery pack being positioned to the vehicle body; thebattery pack comprising a battery module, a box assembly and a firstadhesive member; the box assembly having an accommodating cavity, thebattery module being positioned in the accommodating cavity of the boxassembly; the battery module comprising first batteries arrangedsequentially in a horizontal direction; the first battery comprising anelectrode assembly and a case, and the electrode assembly being receivedin the case; the electrode assembly comprising a first electrode plate,a second electrode plate and a separator provided between the firstelectrode plate and the second electrode plate; the electrode assemblybeing a winding structure and in a flat shape, and the electrodeassembly comprising two flat surfaces, the two flat surfaces facing eachother in a vertical direction; or, the electrode assembly being astacking structure, the first electrode plate, the separator and thesecond electrode plate being stacked in the vertical direction; the boxassembly having a connection portion, and the connection portion beingpositioned at a side of the battery module in the vertical direction; anouter surface of the case comprising a first surface, and the firstsurface being connected with the connection portion via the firstadhesive member; an area A of the first surface and an elastic modulus Bof the first adhesive member satisfying a relationship:0.02 cm²/MPa≤A/B≤9 cm²/MPa.
 18. The vehicle according to claim 17,wherein the box assembly comprises an upper box cover and a lower boxbody, the upper box cover and the lower box body are connected; theconnection portion is a bottom wall of the lower box body, the firstadhesive member is provided to the bottom wall of the lower box body,and the first surface is connected with the bottom wall of the lower boxbody via the first adhesive member; or, the connection portion is a topwall of the upper box cover, the first adhesive member is provided tothe top wall of the upper box cover, and the first surface is connectedwith the top wall of the upper box cover via the first adhesive member.19. The vehicle according to claim 17, wherein the box assemblycomprises an upper box cover, a lower box body and a fixing plate, theupper box cover and the lower box body are connected, the connectionportion is the fixing plate; the fixing plate is positioned at an upperside of the battery module in the vertical direction and connected withthe upper box cover, the first adhesive member is provided on the fixingplate, and the first surface is connected with the fixing plate via thefirst adhesive member; or, the fixing plate is positioned at a lowerside of the battery module in the vertical direction and connected withthe lower box body, the first adhesive member is provided on the fixingplate, and the first surface is connected with the fixing plate via thefirst adhesive member.
 20. An apparatus, comprising a battery packaccording to claim 1, wherein the battery pack is adapted to providepower for the apparatus.